1. Field of the Invention
The present invention relates generally to the field of fuel cells, and in particular to a device for controlling a fuel cell system and a method for performing the control operation for the fuel cell system.
2. Description of the Prior Art
Fuel cells are an electro-chemical device that make use of electro-chemical reaction between a fuel, such as hydrogen, and an oxidizer, such as oxygen contained in the surrounding air, to generate electrical power. The fuel cells are advantageous in low contamination, high efficiency and high power density. Thus, developments and researches are intensively devoted to the fuel cell field for exploitation of the utilization thereof. A variety of fuel cells are available, among which proton exchange membrane fuel cell, abbreviated as PEMFC, is the most prospective one due to the advantages of low operation temperature, fast activation and high power density with respect to unit weight and volume.
A typical fuel cell stack is comprised of a number of membrane electrode assemblies (MEA). Each MEA comprises an anode catalyst layer, a polymeric proton exchange membrane and a cathode catalyst layer. A basic cell can be formed by coupling the MEA with two gas diffusers and a bipolar plate in an overlapping and stacked manner.
The operation of the fuel cells is dependent upon the proton exchange membrane that functions to convey protons between the cathode and the anode of the fuel cell for the progress of the electro-chemical reaction. The performance of the fuel cells is heavily dependent upon the reaction conditions, such as operation temperature, hydrogen flow rate and air flow rate. On the other hand, the operation safety of the fuel cells is dependent upon output voltage and current of the fuel cells. Besides the above factors that affect the overall performance/effectiveness of the fuel cells, in order to realize the optimum performance and safe operation of the fuel cells, additional effective control measures are required.